The present invention concerns improvements in combustion chambers for compression-ignition engines, that is, diesel engines.
In diesel engines of the type having precombustion chambers each combustion chamber is generally formed partly in the cylinder head and partly in the crown of the associated piston. At the end of the compression stroke fuel is injected into the portion of the combustion chamber located in the cylinder head, known as the precombustion chamber, in which the combustion starts. Subsequently a flame front is propagated, through an appropriate suitably shaped channel, from the precombustion chamber to a secondary combustion chamber formed in the piston crown, transmitting to the piston the driving thrust produced by the pressure of the burnt gases. The operating characteristics of the engine, such as, for example, power, specific consumption, noise and degree of smoke, are in part determined by the conformation of the aforesaid and the channel interconnecting them.
The object of the present invention is to improve the operating characteristics of a diesel engine of the aforesaid type, by suitably increasing the size of the secondary chamber and so shaping it as to ensure efficient exhaustion of the combustion gases.